Diesel engine connecting rod bolted joint opening analysis with analytic and finite element models 2010-36-0244

Connecting rods of internal combustion engines usually apply a bolted joint solution at the big end for the assembly with the crankshaft, and in addition, to simplify disassembling. Consequently, a typical engine connecting rod is formed by a stem and a cap that are joined by bolts. However, the engine dynamic loads can be enough to overload the joint causing the cap detachment of the stem. Therefore, the main goal of this paper is to evaluate if the engine dynamic loads are sufficient to cause the unilateral opening of the joint surface that can lead to a catastrophic failure of the engine. The calculation is done by analytical approach and also, by finite element model. The analytical formulation achieved critical results based on conservative hypotheses, while the numerical results indicated a certain security regarding the unilateral opening of the joint surface, pointing to the direction of bolted joints development based on finite element models.